鹽和糖的保質期，遠比你想象的長
Many of the foods that last for a long time are high in sugar and salt.
很多保質期很長的食物都含有很多糖和鹽。
In simple terms, they draw water out, so if bacteria try to grow on it, they will simply shrivel up.
簡單講，這是因爲它們能把水分吸出來，所以如果細菌嘗試在上面生長就會失水變幹。
This is why we use salt to make ham, sugar to make jam, and both to make gravlax.
也正是因爲這個，我們纔會用鹽來製作火腿，纔會用糖來製作果醬，纔會同時用這兩種東西來製作漬鮭魚片。
As foods in their own right, if salt and sugar are stored away from moisture in airtight containers, they will last indefinitely.
而鹽和糖作爲食物本身來講，如果能存放在隔絕水分的密閉容器裏，它們就能夠保質到天荒地老。
But additives, such as iodine added to salt, can reduce its shelf life to about five years.
但是，鹽裏面的食品添加劑，比如碘，則可能把它的保質期縮短至五年。
